The present invention relates to a method of leveling an existing sidewalk which has had portions settle into the ground so as to become uneven over time. More specifically, a method of carefully raising a section of sunken sidewalk so as not to damage the section and allow for the injection of pressurized mason's sand into the cavity created between the bottom of the sidewalk slab and the settled ground.
Regardless of the skill and care used in the initial construction, sidewalks tend to become misaligned over time due to different rates of settlement of the earth. Uplift from freeze/thaw cycles, or tree root lifting are also common causes of sidewalk misalignment. These problems cause cracks in the sidewalk to develop and can also cause step-like structures to occur between sections of the sidewalk. The end result of this condition is the creation of hazards to sidewalk users and liability for those who are responsible for their care. Additionally, the uneven sidewalks are extremely difficult to effectively clear of snow and ice during the winter months in the northern areas of the United States, thus creating further hazards and liabilities for their users and owners.
In the past, there was a number of ways this problem was solved. One of these was to completely remove the damaged section of sidewalk and then re-pour it. The problem with this method is that although it works very well, it is time consuming and very expensive. The re-pour method also results in a checkerboard looking sidewalk as new portion are often a very different color from the older weathered sections. Another method that has been used with the step formation problem is to construct concrete or tar ramps from the lower portion of the sidewalk to the upper. The problem with this method is that it still leaves uneven sidewalk surfaces that are hazardous and difficult to maintain.
Finally, another method that is often used is mud jacking. In this repair method a hole is drilled through the uneven slab and wet mud is pumped under the slab until the slab becomes level. The first problem with this method it that it requires the drilling and patching of unsightly holes in each individual slab of cement. Second, as the mud is pumped under the slab, this method will not repair sections that have raised rather then settled. Finally, the use of wet mud often makes it difficult to effectively level a slab as the mud will settle over time while drying.
More recently, a number of patents have issued that attempt to deal with this problem in an effective and cost efficient manner. In U.S. Pat. No. 4,962,913, Stewart, Oct. 16, 1990, a method of lifting and repairing such damaged sidewalks is provided. The problem with this device is that by nature of its construction, a heavy frame supported by four wheels, it is large and cumbersome in operation. Further, this device requires the even lifting of a given slab in only in small sections at a time, as one portion of the device rests on an unlifted portion of sidewalk. In U.S. Pat. No. 4,982,930, Stewart, Jan. 8, 1991, the same inventor attempted to resolve the short comings of his prior art by lightening the frame and removing the wheels. However, the resulting apparatus is still large and cumbersome in its operation. Also as can be seen both of these lifting methods by Stewart block the walkway while the repair is in progress.
Therefore, from the foregoing discussion it can be clearly seen that it would be highly desirable to provide a means of leveling existing sidewalks in an inexpensive manner that is compact and easily used. The present invention addresses the foregoing problems by providing a pair of small, lightweight towers that attach to and lift either side of a damaged sidewalk so that mason's sand may be injected into the created cavity beneath it. Furthermore, the present invention also offers other advantages over the prior art and solves problems associated therewith.